In the manufacture or repair of products that include a sealed compartment, various methods have been used to determine how well the compartment is sealed, and where water or air intrusion (or extrusion) might occur. In the case of vehicles, for example, it is important to verify that water will not leak into the passenger compartment. Since visual inspection can be highly unreliable, certain vehicle manufacturers utilize spray booths for subjecting fully assembled vehicles to an intense water spray to ensure that vehicles shipped from the factory will not leak due to faulty or damaged seals. While this type of testing can be fairly reliable, it requires a worker to check for the presence of water in the cabin, and it is destructive in the sense that it can cause significant water intrusion in poorly sealed vehicles, or in vehicles where a window or door has been inadvertently left partially open, requiring significant expenditure of time and material for repairs due to water damage. Additionally, the spray booths are expensive to install and maintain, and cannot be easily duplicated at vehicle service and repair facilities. Accordingly, what is needed is method of testing the sealing effectiveness of a sealed compartment that is non-destructive, automatic, and easy and cost effective to implement.